This application claims foreign priority under 35 USC xc2xa7119 to prior foreign application 102 27 484.3 filed in Germany on Jun. 19, 2002.
The invention relates generally to agricultural harvesting machines and, more specifically, to an apparatus and a method for position control of a crop pickup device.
Agricultural harvesting machines generally pick up crop by a crop pickup device. The crop pickup device has the function of picking up the crop to the ground without crop losses and without damage to the crop pickup device or to the ground.
Crop pickup devices are commonly referred to as headers, such as grain headers, forage headers, and corn headers. Crop pick devices generally cut the crop from the field before picking up the crop. Some crop devices, such as corn pickers and grain strippers, separate the cobs or the ears from the crop and then pick them up. Other crop devices pick up the crop previously cut from the field and gather the cut crop into a swath.
To avoid damage to the crop pickup device or the ground, as well as to provide efficient pickup of the crop, the maintenance of a given distance from the crop pickup device to the ground is required. For this purpose, the feeder housing, which carries the crop pickup device, can be pivoted by means of hydraulic cylinders linked to the frame of the agricultural harvesting machine. In this manner, the working height of the crop pickup device can be adjusted. It has proved particularly advantageous to detect the distance from the crop pickup device to the ground by a mechanical ground sensor. Through the use of a subsequent control device, a constant working height of the crop pickup device above the ground can be maintained.
If the crop pickup device has a huge working width, it is necessary to determine the distance to the ground at several points distributed across the working width for satisfactory vertical guiding. For this purpose several ground sensors can be arranged on the crop pickup device, as is known for example from DE 38 07 610, on the lower side of a grain header.
The grain header disclosed in DE 38 07 610 has ground sensors mounted in pairs at the outer ends of the bottom of the header and behind the finger bar. Each pair of ground sensors delivers one distance value to the ground. The two ground distance values are processed by a control device in such a way that the mean value determines the adjustment of the feeder housing, and hence the working height of the grain header above the ground. The grain header shown in DE 38 07 610 is carried by two vertical lifting cylinders arranged on the sidewalls of the feeder housing. A controlled movement of the lifting cylinders can pivot the grain header about a central axis of the harvester. The ground distance values determined by the ground sensors are used in return by a control device to control the transverse inclination of the grain header by means of lifting cylinders, so that a uniform working height of the grain header is obtained; and hence, providing a uniform cutting height of the finger bar. Unilateral sinking of a front wheel or a change of inclination of the field terrain is detected by the ground sensors and the crop pickup device is automatically leveled out. However, the ground sensors detect the ground profile only after picking up the crop, with the result that automatic ground simulation is triggered too late, and there can be damage to the finger bar as well as to the ground. Further, it is not possible to maintain a uniform cutting height, particularly when the ground contour or profile has changed. For instance, when cutting against a slope, too short a cutting height can be achieved with this arrangement of the ground sensors.
DE 295 19 842 U1 discloses a hillside combine harvester having a swinging adapter at the front end of the feeder housing. A hydraulic control device can pivot the grain header mounted thereon about a horizontal axis. Lifting cylinders engaging the swinging adapter can effect suitable adaptation of the cutting angle of the grain header. Thus, it is also possible to adjust the cutting angle of the header for adaptation to different cutting heights. However, this kind of set up does not allow for instantaneous adjustment relative to the slope of the ground. Therefore, particularly when the height of the ground has changed, the cutting angle cannot be optimally adjusted.
It is further known, for example from DE 44 06 892 A1, that the distance from a crop pickup device to the ground can be sensed contactlessly by a ground distance sensor arranged in a crop divider. By this means, a rapid reaction of ground simulation to ground variation becomes possible as different cutting heights of the headers are necessary, particularly when the ground is rising or falling in the direction of travel. This may lead to early lowering of the header which can lead to placement of the header trough on the ground and hence damage the header.
The present invention is directed to overcoming one or more of the problems set forth above.
In accordance with one aspect of the present invention there is provided a position control apparatus for a crop pickup device; means for mounting the crop pickup device for vertical movement relative to an agricultural harvesting machine; measuring means for determining distances from the crop pickup device to the ground at a plurality of points spaced from each other in a direction of travel of the agricultural harvesting machine; a control device for adjusting a position of the crop pickup device relative to the ground as a function of the determined distances.
In accordance with another aspect there is provided a method for position control of a crop pickup device mounted on an agricultural harvesting machine for at least vertical movement relative thereto, and with at least one measuring device for determining the distance from the crop pickup device to the ground, the method comprising the steps of measuring a distance to the ground at a plurality of points spaced apart from each other in the direction of travel; and automatically adjusting a position of the crop pickup device relative to the ground as a function of the measured distances and in conjunction with at least one nominal working position.
The measuring device determines the distance to the ground at two or more points spaced from each other in the direction of travel. As a result, determination of the inclination of the crop pickup device in relation to the slope of the ground is possible. Thus, a control device connected to the measuring device can determine the variation in inclination of the ground profile and use this data for optimum control of the cutting height. Furthermore, sinking of the machine in difficult ground conditions or the use of different tire diameters on the agricultural harvesting machine can be detected with reference to altered distances to the ground. Too low or too high a setting of the crop pickup device relative to the ground is reliably detected, and damage to the crop pickup device or to the ground is advantageously avoided. Further, crop losses are reduced.
With a corresponding movable arrangement of the crop pickup device about a longitudinal or central axis of the agricultural harvesting machine, the transverse inclination of the crop pickup device can be advantageously adjusted automatically by a control device as a function of at least two measured distances in conjunction with a nominal working position.
A further advantageous embodiment of the invention arises if the crop pickup device is arranged to be movable about a transverse axis in relation to the agricultural harvesting machine, and automatic adjustment of the longitudinal inclination of the crop pickup device about the transverse axis as a function of two offset measured distances in conjunction with at least one nominal working position.
In particular, the cutting height of a crop pickup device constructed as a header can be determined from two offset ground distance values spaced apart from each other in the direction of travel, and adjusted automatically by a control device accordingly in conjunction with a selected cutting height. As a result, improved maintenance of the desired cutting height is obtained, particularly when the inclination of the ground changes.
By simultaneous determination of the distance to the ground the accuracy of determination of the inclination of the ground relative to the crop pickup device can be further increased, and the corresponding controls of the position of the crop pickup device, that is, maintenance of the distance to the ground, can be improved considerably.
In an embodiment of the invention, the measuring devices determine a first distance to the ground at a point located ahead of crop pickup, and a further measured distance to the ground at a point located behind crop pickup. As a result, considerable distance between the two points offset in the direction of travel at which the ground is scanned is achieved. This advantageously provides accurate determination of the position of the crop pickup device relative to the ground. Furthermore, advantageously, by first scanning ahead before the crop pickup and then scanning the distance to the ground in the region of the crop pickup device achieves reliable monitoring of the height of the crop pickup device above the ground. Further, almost exact control of the position of the crop pickup device relative to the ground is possible, so that damage to the crop pickup device and to the ground is reduced and harvesting losses are advantageously avoided.
In a further embodiment of the invention, the measuring devices on the agricultural harvesting machine determine the distance to the ground at two points located one behind the other on one track in the direction of travel. This determination yields accurate determination of the ground contour or of the crop pickup device position in relation to the ground in the direction of travel. For the first time by this means the so called cutting angle of the crop pickup device can be automatically adjusted and guided by a control device according to the sensed orientation of the crop pickup device relative to the ground and a given nominal standard. That is, the crop pickup device can be pivoted about a horizontal transverse axis and about a central axis for maintenance of the cutting angle. In particular for headers and corn headers, the cutting angle can advantageously be kept automatically controlled in the working mode of the agricultural harvesting machine, in which case it is completely irrelevant whether the agricultural harvesting machine is harvesting uphill or downhill or different cutting heights are selected or the drive wheels sink into the ground. The crop pickup device is in this case, with corresponding linkage to the agricultural harvesting machine, guided automatically in the position relative to the ground advantageously with a constant cutting angle and with a constant cutting height. As a result, optimum crop pickup and a uniform stubble height are obtained.
In a particular embodiment of the invention, the crop pickup device is carried by a feeder housing, mounted vertically movably on the agricultural harvesting machine, and on the side of the feeder housing facing towards the crop pickup device is arranged a measuring device. Such an arrangement advantageously affords the possibility that the measuring device can be used independently of the crop pickup devices and moreover, when the crop pickup device is removed, as is the case during transport travel of the agricultural harvesting machine, the measuring device can remain on the agricultural harvesting machine. As a result, an electrical coupling between the header and feeder housing is possible. This also provides a considerable distance between the first and the second scanning points of the measuring device with the scanning points being spaced apart in the direction of travel.
In an advantageous manner, the measuring device is arranged above the crop and from there determines the distance to the ground. Due to this arrangement, combined use of the measured distance values is possible. For example, from the measured distance values of a crop edge measuring device arranged above the standing crop, the distance to the standing crop ahead can be determined and the variation in inclination of the standing crop or ground can be detected longitudinally as well as transversely and used for adjustment of the position of the crop pickup device relative to the ground. With this arrangement for viewing far ahead and hence early contact-free scanning of changes in the ground profile can be carried out and the crop pickup device can be guided accordingly. Further, as a result of the arrangement above the crop the very delicate measuring devices are protected from damage and can be provided structurally with simpler housings.
In another aspect, an inclination of the crop pickup device relative to the level is determined by a measuring device arranged on the crop pickup device and used to control the position of the crop pickup device relative to the ground. Determination of the distance to the ground and corresponding control of the position of the crop pickup device relative to the ground advantageously afford the possibility of also determining the inclination of the ground, by a measurement of the inclination of the crop pickup device. By this inclination value, advantageously control systems, which depend on the inclination of the ground, can make adjustments relative to the ground profile ahead.
In a further embodiment of the invention, the cutting height of a crop pickup device constructed as a header is determined from two offset ground distance values spaced apart from each other in the direction of travel, and the cutting height is automatically adjusted in conjunction with a nominal cutting height by a control device according to the measured ground distance values. By the two measured distances to the ground, advantageously the ground contour or profile relative to the crop pickup device and in particular the position of a cutting device such as a finger bar on the crop pickup device and hence the cutting height can be calculated in conjunction with the arrangement of the measuring device on the crop pickup device. As a result, more precise maintenance of the desired cutting height can be obtained on varying terrain too.
Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.